Catheter with composite insert support member

ABSTRACT

An irrigated electrophysiology catheter has a tip electrode having a shell, and a support member configured to plug the shell and support one or more tip components and/or facilitate their functions. Advantageously, the support member has an electrically-conductive interface portion and an insert-molded portion, wherein the interface portion, typically constructed of a precious metal alloy, is structurally minimized, yet still configured for electrical connection with the shell and the lead wire, so as to reduce the amount and hence the cost of its manufacture, whereas the insert-molded portion is constructed of a significantly less-costly material and is readily configured with micro-complex 3-D geometry adapted to support tip structure and functions including irrigation, force sensing and temperature sensing, as a further cost savings in the manufacturing of the tip electrode by reducing materials, labor and time.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a division of and claims priority to and the benefitof U.S. patent application Ser. No. 15/622,018, filed Jun. 13, 2017, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to electrophysiologic (EP) catheters, inparticular, EP catheters for ablating cardiac tissue.

BACKGROUND

Electrode catheters have been in common use in medical practice for manyyears. Diagnosis and treatment of cardiac arrythmias by means ofelectrode catheters include mapping the electrical properties of hearttissue and selectively ablating cardiac tissue by application of energy.Such ablation can cease or modify the propagation of unwanted electricalsignals from one portion of the heart to another. The ablation processdestroys the unwanted electrical pathways by formation of non-conductinglesions. Various energy delivery modalities have been disclosed forforming lesions, and include use of microwave, laser and more commonly,radiofrequency energies to create conduction blocks along the cardiactissue wall.

In a two-step procedure—mapping followed by ablation—electrical activityat locations within the heart is typically sensed and measured byadvancing a catheter containing one or more electrical sensors (orelectrodes) into the heart, and acquiring data at a multiplicity oflocations. These data are then utilized to select the tissue targetareas at which ablation is to be performed.

In use, the electrode catheter is inserted into a major vein or artery,e.g., the femoral artery, and then guided into the chamber of the heartwhich is of concern. A reference electrode is provided, generally tapedto the patient's skin or provided on the ablation catheter or anothercatheter. Radio frequency (RF) current is applied to the ablationelectrode of the catheter, and flows through the surrounding media,i.e., blood and tissue, toward the reference electrode. The distributionof current depends on the amount of electrode surface in contact withthe tissue, as compared to blood which has a higher conductivity thanthe tissue.

The distal tip electrode of conventional irrigated catheters employs atwo-part configuration, with a thin dome electrode shell having anopening and an interior cavity, and an insert support member that sitsin and plugs the opening sealing the interior cavity. The shell, whichmay be formed by any suitable method, including, for example, stamping,deep drawing or conventional machining, and the insert support memberare both constructed of electrically-conductive material, includingpalladium/platinum alloy or similar precious metal alloy so thatelectrical connection supplying electrically energy to the insertsupport member is conducted to the shell during ablation procedures. Theinsert support member thus serves to provide a physical connection tothe shell allowing laser welding or other suitable permanent connectionbetween the shell and the insert support member and providing anelectrical connection to the shell. With conventional catheters enabledwith multiple functions, including, irrigation, position sensing,temperature sensing and RF ablation, the insert support memberincorporates a complex geometry in order to accommodate a multitude ofcomponents in a very compact region.

Not only does the use of precious metal alloys increase the cost of theinsert support member, but intricate, micro-machining to produce thecomplex geometry can increase the cost of manufacture significantly.Accordingly, there is a desire for an insert support member which can beformed from a less-costly material and by a less-costly method, whilemeeting the requirements of complex geometry, electrical conductivityand permanent connection. There is a desire for the insert supportmember to have a structure and configuration better suited for low cost,high volume manufacturing and further, for integration of componentssuch as a temperature sensor and reduction of additional components suchas polyimide insulation spacers and tubes.

SUMMARY OF THE INVENTION

An irrigated electrophysiology catheter has a tip electrode having ashell, and a support member configured to plug the shell and support oneor more tip components and/or facilitate their functions.Advantageously, the support member has an electrically-conductiveinterface portion and an insert-molded portion, wherein the interfaceportion, typically constructed of a precious metal alloy, isstructurally minimized, yet still configured for electrical connectionwith the shell and the lead wire, so as to reduce the amount and hencethe cost of its manufacture, whereas the insert-molded portion isconstructed of a significantly less-costly material and is readilyconfigured with micro-complex 3-D geometry adapted to support tipstructure and functions including irrigation, force sensing andtemperature sensing, as a further cost savings in the manufacturing ofthe tip electrode by reducing materials, labor and time.

In some embodiments of the present invention, an electrophysiologycatheter has an elongated catheter body, a lead wire, and a tipelectrode. Configured for irrigation, the tip electrode and has a shelland a support member. The shell has a proximal opening and an interiorcavity. The support member advantageously has an electrically-conductiveinterface portion, such as a precious metal alloy, and an insert-moldedportion of a plastic material, the interface portion being in electricalconnection with the shell and the lead wire, and the interface portionhaving a peripheral portion engaged with the shell at the proximalopening.

In some detailed embodiments, the insert-molded portion includes adistal portion in the interior cavity of the shell.

In some detailed embodiments, the insert-molded portion includes aproximal portion proximal of the peripheral portion of the interfaceportion.

In some detailed embodiments, the insert-molded portion has a fluidpassage.

In some detailed embodiments, the insert-molded member has a fluidaperture.

In some detailed embodiments, the insert-molded portion has alongitudinal passage configured to receive a tensile component.

In some detailed embodiments, the insert-molded portion has a proximalextension having an outer surface with an outer surface of the interfaceportion.

In some detailed embodiments, the insert-molded portion has acircumferential indentation configured to receive a ring electrode,including, for example, an insert-molded ring electrode.

In some detailed embodiments, the insert-molded portion has an annularflange configured to receive a portion of a component, including, forexample, a force sensor.

In some detailed embodiments, the insert-molded portion has a notchconfigured to allow passage of the lead wire connected to the ringelectrode.

In some detailed embodiments, the insert-molded portion has a recessconfigured to receive a component, including, for example, a thermistor.

In some embodiments of the present invention, a method of manufacturingan electrophysiology catheter with a tip electrode, comprising (a)providing a shell, the shell having an interior cavity, (b) providing asupport member with an interface portion of one material, including aprecious metal alloy, and an insert-molded support member of anothermaterial, including plastic, including (i) configuring a thin sheet toform the interface portion, and (ii) insert molding the interfaceportion with the insert-molded portion, wherein the interface portion isconfigured to engage with the shell with a distal portion of theinsert-molded portion positioned in the interior cavity.

In some detailed embodiments, the configuring a thin sheet to form theinterface portion includes providing the interface portion with anelectrical connection member.

In some detailed embodiments, the insert molding the interface portionincludes exposing a portion of the electrical connection member forconnection to a lead wire.

In some detailed embodiments, the electrical connection member projectsfrom an opening formed in the interface portion and extends proximallythrough the opening.

In some detailed embodiments, the configuring a thin sheet to form theinterface portion includes forming the interface portion with an openingthrough which the insert-molded portion extends.

In some detailed embodiments, the configuring a thin sheet to form theinterface portion includes forming an interlock projection configured tobe surrounded by the insert-molded portion.

In some detailed embodiments, the configuring a thin sheet to form theinterface portion includes forming a peripheral portion configured foran interference fit with a proximal rim of the shell.

In some detailed embodiments, the peripheral portion has a step having adistal portion to engage with the proximal shell.

In some detailed embodiments, the method further comprises insertmolding a ring electrode onto the insert-molded portion.

In some detailed embodiments, the method further comprises insertmolding a connector sleeve onto the insert-molded portion.

In some embodiments, a method of manufacturing an electrophysiologycatheter with a tip electrode, comprises (a) providing a shell, theshell having an interior cavity, (b) providing a support member with aninterface portion of a metal alloy and an insert-molded portion of aplastic material, including: (i) configuring a thin sheet of the metalalloy to form the interface portion, and (ii) insert molding theinterface portion with the plastic material to form the insert-moldedportion, wherein the interface portion is configured to engage with theshell with a distal portion of the insert-molded portion positioned inthe interior cavity of the shell, and (c) mounting the shell onto thesupport member, wherein the interface portion is engaged with the shelland a distal peripheral portion of the interface portion has aninterference fit with a proximal opening of the shell.

In some detailed embodiments, wherein the insert molding the interfaceportion with the plastic material to form the insert-molded portionincludes forming a circumferential indentation on an outer surface onthe insert-molded portion, and the method further comprises insertmolding a ring electrode in the circumferential indentation.

In some detailed embodiments, wherein the insert molding the interfaceportion with the plastic material to form the insert-molded portionincludes forming a recess, and the method further comprises insertmolding a thermistor in the recess.

In some detailed embodiments, wherein the insert molding the interfaceportion with the plastic material to form the insert-molded portionincludes forming a fluid passage.

In some detailed embodiments, wherein the insert molding the interfaceportion with the plastic material to form the insert-molded portionincludes forming a fluid aperture.

In some detailed embodiments, wherein the insert molding the interfaceportion with the plastic material to form the insert-molded portionincludes forming an annular flange configured to receive a distal end ofa force sensor.

In some detailed embodiments, the mounting the shell onto the supportmember includes forming a laser welding bond between the shell and theinterface portion.

In some detailed embodiments, the configuring a thin sheet of the metalalloy to form the interface portion includes forming an electricalconnection member, and the insert molding the interface portion with theplastic material to form the insert-molded portion includes exposing atleast a portion of the electrical connection member configured forconnection to an electrical energy conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings. It isunderstood that selected structures and features have not been shown incertain drawings so as to provide better viewing of the remainingstructures and features.

FIG. 1 is a perspective view of a catheter of the present invention, inaccordance with an embodiment.

FIG. 2 is an end cross-sectional view of a catheter body of the catheterof FIG. 1, taken along line A-A.

FIG. 3 is an end cross-sectional view of an intermediate deflectionsection of the catheter of FIG. 1, taken along line B-B.

FIG. 4 is a side view of a distal section of the catheter of FIG. 1,with part(s) broken away.

FIG. 5 is a schematic representation of magnetic coil components housedin the distal section, in accordance with one embodiment.

FIG. 6A is a side cross-sectional view of a shell and an insert member,in accordance with an embodiment of the present invention.

FIG. 6B is a detailed side cross-sectional view of a proximal portion ofan insert member and a flex circuit, in accordance with anotherembodiment of the present invention.

FIG. 7A is a perspective view of an insert member, in accordance with anembodiment of the present invention.

FIG. 7B is a perspective view of an insert member, in accordance withanother embodiment of the present invention.

FIG. 7C is a perspective view of an insert member, in accordance withyet another embodiment of the present invention.

FIG. 8 is a perspective view of an interface portion of the insertmember, in accordance with an embodiment of the present invention.

FIG. 9A is an end cross-sectional view of the tip electrode of FIG. 6A,taken along line A-A.

FIG. 9B is an end cross-sectional view of the tip electrode of FIG. 6A,taken along line B-B.

FIG. 9C is an end cross-sectional view of the tip electrode of FIG. 6A,taken along line C-C.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an embodiment of a catheter 10 with an improvedirrigation-cooled ablation tip electrode. The catheter has an elongatedcatheter body 12 with proximal and distal ends, an intermediatedeflectable section 14 at the distal end of the catheter body 12, and adistal section 15 with a tip electrode 17. The catheter also includes acontrol handle 16 at the proximal end of the catheter body 12 forcontrolling deflection (single or bi-directional) of the intermediatesection 14 relative to the catheter body 12.

With reference to FIG. 2, the catheter body 12 comprises an elongatedtubular construction having a single, axial or central lumen 18. Thecatheter body 12 is flexible, i.e., bendable, but substantiallynon-compressible along its length. The catheter body 12 can be of anysuitable construction and made of any suitable material. A presentlypreferred construction comprises an outer wall 20 made of polyurethaneor PEBAX. The outer wall 20 comprises an imbedded braided mesh ofstainless steel or the like to increase torsional stiffness of thecatheter body 12 so that, when the control handle 16 is rotated, theintermediate section 14 of the catheter 10 will rotate in acorresponding manner.

The outer diameter of the catheter body 12 is not critical, but ispreferably no more than about 8 french, more preferably 7 french.Likewise the thickness of the outer wall 20 is not critical, but is thinenough so that the central lumen 18 can accommodate puller members(e.g., puller wires), lead wires, and any other desired wires, cables ortubings. If desired, the inner surface of the outer wall 20 is linedwith a stiffening tube 22 to provide improved torsional stability. Adisclosed embodiment, the catheter has an outer wall 20 with an outerdiameter of from about 0.090 inch to about 0.94 inch and an innerdiameter of from about 0.061 inch to about 0.065 inch.

Components that extend between the control handle 16 and the deflectablesection 14 pass through the central lumen 18 of the catheter body 12.These components may include lead wires 30T and 30R (for the tipelectrode 17 and one or more ring electrodes 21 proximal of the tipelectrode), an irrigation tubing 38 with lumen 39 for delivering fluidto the tip electrode, a cable 33 for a position sensor 34 carried in ornear the distal section 15, puller wires 32 a, 32 b for deflecting theintermediate section 14, and a pair of thermocouple wires 41, 42 tosense temperature at the distal section 15.

Illustrated in FIG. 3 is an embodiment of the intermediate section 14which comprises a short section of tubing 19. The tubing has multiplelumens, for example off-axis lumens 24, 26 a, 26 b, 27 and on-axis lumen28. The lumen 24 carries the lead wires 30T and 30R, and thethermocouple wires 41 and 42. The lumen 27 carries the position sensorcable 33. The lumen 28 carries the irrigation tubing 38. The lumen 26 acarries a puller wire 32 a for deflection of the intermediate section.For bi-directional deflection, the diametrically-opposing lumen 26 bcarries a second puller wire 32 b. It is understood that the pluralityand arrangement of the lumens of the tubing 19 may vary as needed orappropriate. For example, in other embodiments, the tubing 19 may havetwo opposing lumens for puller wires, with two more lumens about 90degrees therefrom, for routing all other components.

The tubing 19 of the intermediate section 14 is made of a suitablenon-toxic material that is more flexible than the catheter body 12. Asuitable material for the tubing 19 is braided polyurethane, i.e.,polyurethane with an embedded mesh of braided stainless steel or thelike. The size of each lumen is not critical, but is sufficient to housethe respective components extending therethrough.

Each puller wire 32 a and 32 b has a lubricious coating, e.g. ofTeflon®. The puller wires can be made of any suitable metal, such asstainless steel or Nitinol and the Teflon coating imparts lubricity tothe puller wire. The puller wire preferably has a diameter ranging fromabout 0.006 to about 0.010 inch.

As shown in FIG. 3, the portion of each puller wire in the catheter body12 passes through a compression coil 35 in surrounding relation to itspuller wire. Each compression coil 35 extends from the proximal end ofthe catheter body 12 to at or near the proximal end of the intermediatesection 14. The compression coils are made of any suitable metal,preferably stainless steel, and are tightly wound on themselves toprovide flexibility, i.e., bending, but to resist compression. The innerdiameter of the compression coil is preferably slightly larger than thediameter of the puller wire. Each portion of the puller wires distal ofthe compression coil 35 may extend through a respective protectivesheath 37 to prevent the puller wire from cutting into the tubing 19 ofthe intermediate section 14 during deflection.

Proximal ends of the puller wires 32 a and 32 b are anchored in thecontrol handle 16. Distal ends of the puller wires 32 a and 32 b areanchored at or near the distal end of the tubing 19 of the intermediatesection 14, as understood by one of ordinary skill in the art. In someembodiments, T-bars 25 may be used to anchor the distal ends of thepuller wires near the distal end of the tubing 19, as shown in FIG. 4).In other embodiments, one or more components or features may be moldedin the tip electrode 17 for looping or otherwise anchoring the pullerwires, as described further below. Separate and independent longitudinalmovements of the puller wires relative to the catheter body 12, whichresults in, respectively, deflection of the intermediate section 14along a plane, are accomplished by suitable manipulation of a deflectionmember of the control handle 16. Suitable deflection members and/ordeflection assemblies are described in co-pending U.S. Publication No.US2010/0168827 A1, published Jul. 1, 2010, entitled DEFLECTABLE SHEATHINTRODUCER, and U.S. Publication No. US2008/0255540 A1, published Oct.16, 2008, entitled STEERING MECHANISM FOR BI-DIRECTIONAL CATHETER, theentire disclosures of both of which are hereby incorporated byreference.

With reference to FIG. 4 and FIG. 6A, at the distal end of theintermediate section 14 is the distal tip section 15 that includes thetip electrode 17 and a relatively short piece of non-conductiveconnector tubing or sleeve 23 between the tip electrode 17 and theintermediate section 14. In the illustrated embodiment, the connectortubing 23 has a single lumen 29 which receives a distal end of theposition sensor cable 33 and allows passage of components includingelectrode lead wires 30T and 30R, thermocouple wires 41 and 42, and theirrigation tubing 38 into the distal section 15 and tip electrode 17.The single lumen 29 of the connector tubing 23 allows these componentsto reorient themselves as needed from their respective lumens in theintermediate section 14 toward their location within the distal section15 and tip electrode 17. In the disclosed embodiment, the tubing 23 is aprotective tubing, having a length ranging between 6 mm and 12 mm.

The connector tubing 23 also houses a force sensor 90. Aspects of aforce sensor similar to force sensor are described in U.S. Pat. No.8,357,152, issued on Jan. 22, 2013 to Govari et al., entitled CATHETERWITH PRESSURE SENSING, and in U.S. Patent Publication No. 2011/0130648,to Beeckler et al., filed Nov. 30, 2009, entitled CATHETER WITH PRESSUREMEASURING TIP, both of whose disclosures are incorporated herein byreference.

The force sensor 90 includes a resilient coupling member 91, which formsa spring joint. In some embodiments, the coupling member 91 has hollowcylindrical form with a central lumen 92 therethrough. Coupling member91 typically has one or more helices 93 cut or otherwise formed in themember, so that the member behaves as a spring. In some embodiments, thecoupling member 91 is formed of a superelastic alloy, such as nickeltitanium (Nitinol), within force sensor 90.

With reference to FIG. 5, the force sensor 90 includes a joint sensingassembly comprising coils 76, 78, 80 and 82 that provides accuratereading of any dimensional change in axial displacement and angulardeflection in the spring joint, including when the tip electrode 17 isangularly displaced from a longitudinal axis 84 of the catheter, such asthen the tip electrode comes into contact with tissue. These coils areone type of magnetic transducer that may be used with the catheter. A“magnetic transducer,” in the context of the present patent applicationand in the claims, means a device that generates a magnetic field inresponse to an applied electrical current and/or outputs an electricalsignal in response to an applied magnetic field. Although theembodiments described herein use coils as magnetic transducers, othertypes of magnetic transducers may be used in alternative embodiments, aswill be apparent to those skilled in the art.

The coils in the sensing assembly are divided between two subassemblieson opposite sides of the spring joint. One subassembly comprises coil 82distal of the spring joint, which is driven by a current, via a wire(included in the cable 33), to generate a magnetic field. This field isreceived by a second subassembly, comprising coils 76, 78 and 80, whichare located proximal of the spring joint, in a section of the connectortubing 23 that is spaced axially apart from and proximal of the coil 82.The term “axial,” as used in the context of the present patentapplication and in the claims, refers to a direction along or parallelto the longitudinal axis 84 of the catheter. The coil 82 typically lieson-axis with the longitudinal axis 84.

The coils 76, 78 and 80 are fixed in connector tubing 23 at the sameproximal distance from the coil 82 but at different radial locations.(The term “radial” refers to coordinates about the longitudinal axis84.) Specifically, in the illustrated embodiment, the coils 76, 78 and80 are all located in the same plane perpendicular to the longitudinalaxis 84 but at different equi-azimuthal angles about the longitudinalaxis 84, that is, the three coils are spaced azimuthally 120 degreesapart at the same axial distance from the coil 82 along the longitudinalaxis 84.

The coils 76, 78 and 80 generate electrical signals in response to themagnetic field transmitted by coil 82. These signals are conveyed bywires (part of the cable 33) extending proximally from the distalsection 15, through the lumen 24 of the intermediate section 14, throughthe lumen 18 of the catheter body 12 and into the control handle 16. Thesignals are processed by a remote processor in order, for example, tomeasure the axial displacement of spring joint along the longitudinalaxis 84, as well as to measure the angular deflection of the joint fromthe longitudinal axis 84. From the measured displacement and deflection,the processor is able to evaluate, typically using a previouslydetermined calibration table, a magnitude and a direction of the forceon the spring joint.

The same processor (or another processor) detects and measures thelocation and orientation of distal section 15. The method of measurementmay be by any convenient process known in the art. In one embodiment,magnetic fields generated external to a patient create electric signalsin elements in the distal section 15, and the processor uses theelectric signal levels to determine the distal section location andorientation. Alternatively, the magnetic fields may be generated in thedistal section 15, and the electrical signals created by the fields maybe measured external to patient. As also shown in FIG. 5, the elementsin distal section 12 that are used to position and locate the distalsection) 12 include orthogonal coil C_(x) aligned with the X axis,orthogonal coil C_(y) aligned with the Y axis, and one of the coil 76,78 and 80 (in addition to their use as elements of force sensor), forexample, the coil 80 aligned with the Z axis as orthogonal coil C_(z).The coils C_(x), C_(y), C_(z)/80 are housed in the connector tubing 23,within the lumen 68 of the coupling member 60. These coils are thesensing components of the electromagnetic position sensor 34 to whichthe cable 33 is connected. In some embodiments, the catheter includes asingle axial sensor (SAS) cable assembly in lieu of the cable 33 and theelectromagnetic position sensor 34 for position and location sensing. ASAS cable assembly suitable for use is described in U.S. Pat. No.8,792,962, titled CATHETER WITH SINGLE AXIAL SENSORS, the entiredisclosure of which is incorporated herein by reference.

With reference to FIG. 4, FIG. 6A and FIG. 7A, the irrigated tipelectrode 17 has a two-piece construction that includes anelectrically-conductive dome shell 50 and a support member 52. The shell50 has a hollow cylindrical body 50B with an open proximal portion (orrim) 50P in communication with an interior cavity 51 defined by a closeddistal portion 50D with a dome atraumatic distal end 53. Formed in wall63 of the shell 50 are a plurality of fluid exit ports 56 that allowfluid communication between the interior cavity and outside the shell50. The support member 52 advantageously has a configuration includingan electrically-conductive interface portion 54 and an insert-moldedportion 55 which functions as a unitary body.

The interface portion 54 (perhaps best seen in FIG. 8) mates or engageswith the shell 50 for electrical conduction. In some embodiments, asillustrated in FIG. 6A, the interface portion 54 has an annularconfiguration (e.g., a ring) such that a peripheral portion 57 providesan interference fit with the proximal opening portion or rim 50P of theshell 50, sealing the rim 50P so that the interior cavity 51 provides aninternal plenum chamber within the shell 50. In some embodiments, across-section of the peripheral portion 57 includes a step S defining arelatively narrower (distal) annular portion 57D that is immediatelydistal of the rim 50P of the shell, and a relatively wider (proximal)annular portion 57P inside of the rim 50P of the shell. The step Sprovides a circumferential surface to which the proximal rim 50P ofshell 50 is attached, e.g., via a laser weld 98, in its circumferentialentirety to provide a durable attachment of the shell to the interfaceportion 54 and thus to the catheter 10.

The interface portion 54 includes an electrical connection member or tab58 to which lead wire 30T is connected for energizing the interfaceportion 54 and thus also the shell 50 in engagement with the interfaceportion 54. A distal inner edge 60 (see FIG. 8) of the peripheralportion 57 surrounds an opening 61 through which the insert-moldedportion 55 extends. To interlock the interface portion 54 with theinsert-molded portion 55, the inner edge 60 is formed with one or moreprojections 62 surrounded by the insert-molded portion 55 and aroundwhich the insert-molded portion 55 is formed, as explained below infurther detail.

In some embodiments, the interface portion 54 is formed from a thinsheet of an electrically-conductive, biocompatible material, such as ametal alloy or precious metal alloy. The shell 50 is also constructed ofthe same or similar electrically-conductive biocompatible material. Asuitable biocompatible metal alloy includes an alloy selected fromstainless steel alloys, noble metal alloys and/or combinations thereof.In one embodiment, the alloy comprises about 80% palladium and about 20%platinum by weight. In an alternate embodiment, the alloy comprisesabout 90% platinum and about 10% iridium by weight. In some embodiments,the shell 50 is formed by deep-drawing manufacturing process whichproduces a sufficiently thin but sturdy shell wall that is suitable forhandling, transport through the patient's body, and tissue contact.

Suitable methods for manufacturing the interface portion 54 from thethin sheet include, for example, stamping, deep drawing and otherconventional methods, to provide the interface portion with its innerand outer edges and 3-D configuration. In particular, the manufacturingmethod provides portions of the thin sheet within the region of theopening 61 to form the tab 58 and the interlock projections 62. In theillustrated embodiment, the portion forming the tab 58 is subsequentlybent or otherwise shaped with a U-bend to extend proximally through theopening 61 at an angle generally perpendicular to a plane defined by theopening 61. In some embodiments, that the interface portion 54 isconfigured and sized such the length L of the tab 58 exceeds the depth Dof the interface portion 54 (see FIG. 6A) to provide easier access whenthe lead wire 30T is attached to the tab 58, with the recognition thatan extension portion can be added to the tab 58 where there is a need ordesire for the length L to be greater than the diameter of the opening61. It is further understood that the tab 58 may be configured in avariety of shapes and sizes so long as the lead wire 30T can beconnected to it, for example, by soldering a wire bond or any otherconventional methods. Electrical energy or signals may be transmitted toor from the interface portion 54 by any suitable conduit, including aflex circuit 75, as shown in the embodiment of FIG. 6B, where a portionof the flex circuit 75 is placed on the proximal face 79 with theremainder portion extending, for example, proximally in the lumen 92 ofthe coupling member 91, and the flex circuit 75 has one or morethru-vias 79 for receiving and soldering to the tab 58 and/or thethermocouple wires 41 and 42.

The insert-molded portion 55 has a distal portion 55D that is distal ofthe interface portion 54, a main portion 55M that is within theinterface portion 54, and a proximal portion 55P that is proximal of theinterface portion 54. In some embodiments, the distal portion 55 isconfigured generally as a solid cylinder that extends into the shell 50,occupying space within the interior cavity 51 defined by the surroundingshell 50. The distal portion 55D has a predetermined diameter or girthand a length that leave a circumferential gap G and a distal gap DGbetween the distal portion 55D and the shell 50. In some embodiments,the main portion 55M extends between the opening 61 and a proximal endof the peripheral portion 57 of the interface portion 54, and is inconformity with the inner surface of the interface portion 54, e.g., viainjection-molding. The main portion 55M is configured to block theopening 61. Notably, the main portion 55M may be formed around the tab58 without interfering with the conductive connection of the tab 58 andthe lead wire 30T. That is, the insert molding of the interface portion54 with a plastic material to form the insert-molded portion 55 leaves aportion of the tab 58 exposed and accessible for connection of asuitable electrical conduit.

Having an injected-molded body, the insert-molded portion 55 isintegrated with the interface portion 54 and thus the members 54 and 55function and perform as a single, unitary body and component. Incomparison to prior support members constructed entirely of a metalalloy, the support member 52 with the members 54 and 55 herein providessimilar effective functions, including plugging the shell, enabling adurable and conductive shell attachment, and providing desirable and/ornecessary complex 3-D geometry in accommodating other functions and/orcomponent layouts in the tip electrode, but at a significantly lessercost due to savings in supply and manufacturing costs. Supply costs arereduced with lesser use of precious metal alloy in the support member,and manufacturing costs are reduced by replacing micro-drilling withinsert molding, including micro-insert molding, the latter of which canproduce more intricate and detailed 3-D geometry.

In some embodiments, the 3-D geometry includes one or more fluidapertures 64 and one or more interconnected fluid passages 65 extendingthrough the length of the insert-molded portion 55. In the illustratedembodiment, the insert-molded portion 55 includes a longitudinal,on-axis fluid passage 65 having a proximal opening at the proximal face79 that receives a distal end of the irrigation tubing 38. The fluidpassage 65 passes through the opening 61 of the interface portion 54 andbranches into axial passage 65A and radial passages 65R which are incommunication with the fluid apertures 64, so that fluid passing fromthe irrigation tubing 38 can exit the fluid apertures 64 and enter theplenum chamber in the interior cavity 51 of the shell 50, and exit theshell 50 via exit ports 56 to outside of the tip electrode 17. The shell50 and the plug 52 facilitate the provision of a plenum condition withinthe interior cavity 51; that is, where fluid is forced or delivered inthe interior cavity 51 and then passes through the exit ports 56 formedin shell wall 63 to exit the tip electrode 17.

In some embodiments, the 3-D geometry includes one or more longitudinalpassages 71 for a safety cord 72 passing therethrough as a safetymeasure against detachment of the tip electrode 17. The longitudinalpassages 71 extend the length of the insert-molded portion 55 and have aU-bend 97 at or near the distal end of the insert-molded portion 55. Insome embodiments, the safety cord 72 passes through the entire length ofthe catheter with a U-bend portion at the U-bend 97 and its proximalends anchored within the control handle 16. In some embodiments, theproximal ends of the safety cord 72 are anchored at a more distallocation, e.g., the bond joint at the distal end of the deflectablesection 14.

In some embodiments, the 3-D geometry includes a distal face 81configured with a recess 95 in which a thermistor 96 is insert-molded,and the insert-molded portion 55 configured with a longitudinal passage73 through its length for the thermistor wires 41 and 42.

In some embodiments, the 3-D geometry includes the proximal portion 55Pconfigured with a proximal extension 55E to the peripheral portion 57 ofthe interface portion 54 so that its outer surface 55S is flush with anouter surface 59 of the interface portion 54. Moreover, the outersurface 55S may be configured with a circumferential indentation 55C foraccommodating ring electrode 21 which may be insert-molded. In someembodiments, the proximal portion 55P is configured with a notch 67 toallow passage of lead wire 30R from the ring electrode 21 into the lumen29 of the connector tubing 23.

In some embodiments, the 3-D geometry includes a proximal face 79 of theinsert-molded portion 55 configured with a recess 68 to receive a distalend of the resilient coupling member 91 of the force sensor 90. In theillustrated embodiment of FIG. 6A, the recess 68 is defined by a thinannular flange 69 that surrounds the distal end of the coupling member91 in positioning the force sensor 90 on-axis with the longitudinal axis84.

In some embodiments, the connector sleeve 23 housing the force sensor 90is overmolded on the support member 52. In some embodiments, theconnector sleeve 23 is over-molded on the proximal face 79 of theinjection-molded portion 55, as shown in FIGS. 6A and 7B, to include aninner annular notch formation defined by an inner diameter at its distalend. In some embodiments, e.g., where the interface portion 54 is slidover the distal end of the connector sleeve 23, the connector sleeve 23has an outer annular notch formation defined by an outer diametersuitable for sliding the interface portion 54 over it.

From the tip electrode 17, the lead wires 30T and 30R, and thethermistor wires 41 and 42 and the irrigation tubing 31 pass proximallythrough the lumen 92 of the coupling member 91, as shown in FIG. 6A, andinto respective lumens of the tubing 19 of the intermediate section 14,as shown in FIG. 3. One or more of these components may be surrounded byone or more protective and/or insulating sleeves, as needed or desired.The lead wires, thermistor wires, and the irrigation tubing pass fromthe lumens of the tubing 19 of the intermediate section 14 and into thelumen 18 of the catheter body 12, as shown in FIG. 2.

In some embodiments, with reference to and incorporation of thedescription above, the tip electrode is manufactured by processes thatinclude:

(1) Providing the shell 50 of a suitable biocompatible metal alloy, theshell having a proximal rim 50P;

(2) Providing the support member 52 having an interface portion 54 andan insert-molded portion 55, including:

-   -   (a) Providing a thin sheet of the same or similar suitable        biocompatible metal alloy;    -   (b) Configuring, for example, stamping, the thin sheet to form        the interface portion 54; including one or more of the        following:        -   (i) forming an opening 61 with one or more interlock            projections 62 and/or one or more electrical connection tab            54;        -   (ii) forming a peripheral portion 57 with a step S having a            distal (narrower) portion 57D and a proximal (wider) portion            57P, the distal portion 57D configured to provide an            interference fit with the proximal rim 50P of the shell 50;            and/or        -   (iii) shaping the electrical connection tab 54, for example,            bending the tab 54 at an angle such that the tab extends            proximally;    -   (c) Insert molding the insert-molded portion 55 onto the        interface portion 54, including one or more of the following:        -   (i) Micro-insert molding the member 55 with one or more of            the following 3-D geometries:            -   1. One or more fluid passages 65, including an axial                passage 65A and/or a radial passage 65R;            -   2. One or more fluid apertures 64, including a fluid                aperture in fluid communication with a fluid passage;            -   3. One or more longitudinal passages 71 and 73,                including a longitudinal passage extending the length of                the infjection-molded member 55;            -   4. Proximal extension 55E, including a proximal                extension 55E having an outer surface even with an outer                surface of the peripheral portion 57 of the interface                portion 54;            -   5. One or more circumferential indentations 55C, (see                FIG. 7B) including a circumferential indentation 55C in                the proximal extension 55E configured to receive a ring                electrode 21, including an insert-molded ring electrode                21;            -   6. Annular flange 69, including an annular flange on a                proximal face, and an annular flange configured to                receive a distal end of a force sensor coupling member                91;            -   7. One or more notches 67, including a notch in the                proximal extension 55E configured to pass a lead wire                30R for the ring electrode 21; and/or            -   8. A recess 95, including a recess on a distal face of                the insert-molded portion 55, including a recess                configured to receive a thermistor 96.        -   (ii) Micro-insert molding the ring electrode 21 in a            circumferential indentation 55C (see FIG. 7B);        -   (iii) Micro-insert molding the thermistor 96 in the recess            95.        -   (iv) Over-molding the member 55 with a connector sleeve 23            (see FIG. 7C) [Jeff, any particular features or method?].

(3) Attaching the shell 50 to the interface portion 54, including:

-   -   (a) Mounting the proximal rim 50P onto the distal portion 57D of        the interface portion 54; and    -   (b) Laser-welding the proximal rim 50P onto the peripheral        portion 57.

It is understood that the terms “injection-molding,” “insert-molding,”and “over-molding,” (and variations thereof) are used interchangeablyherein, as appropriate, to include any process wherein a material isinjected into a mold cavity, where it cools and hardens to theconfiguration of the cavity in forming a molded component. In someapplications, the mold cavity is configured to partially or fully covera first material or substrate in forming the molded component. In someapplications, the mold cavity is configured in or through a firstmaterial or substrate in forming the molded component. Combinations ofthese applications may be employed as appropriate or desired.

The preceding description has been presented with reference to presentlypreferred embodiments of the invention. Workers skilled in the art andtechnology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningfully departing from the principal, spirit and scope ofthis invention. Notably, the drawings are not necessarily to scale, andany one or more features of any one or more embodiments may be includedin any other one or more embodiments in addition to or in lieu of anyfeature, as desired or appropriate. Accordingly, the foregoingdescription should not be read as pertaining only to the precisestructures described and illustrated in the accompanying drawings, butrather should be read consistent with and as support to the followingclaims which are to have their fullest and fair scope.

What is claimed is:
 1. A method of manufacturing a tip electrode of anelectrophysiology catheter, the method comprising: providing a shellhaving an interior cavity; forming a support member with an interfaceportion of an electrically-conductive material and an insert-moldedportion of another material, including: configuring a thin sheet of theelectrically-conductive material to form the interface portion; andforming the insert-molded portion onto the interface portion by insertmolding, wherein the interface portion is configured to engage with theshell and a distal portion of the insert-molding portion is positionedin the interior cavity.
 2. The method of claim 1, wherein theconfiguring the thin sheet of the electrically-conductive material toform the interface portion includes providing the interface portion withan electrical connection member.
 3. The method of claim 2, wherein theforming the support member includes exposing a portion of the electricalconnection member for connection to a lead wire.
 4. The method of claim2, wherein the electrical connection member projects from an openingformed in the interface portion and extends proximally through theopening.
 5. The method of claim 1, wherein the configuring the thinsheet of the electrically-conductive material to form the interfaceportion includes forming the interface portion with an opening throughwhich the insert-molded portion extends.
 6. The method of claim 1,wherein the configuring the thin sheet of the electrically-conductivemember to form the interface portion includes forming an interlockprojection.
 7. The method of claim 1, wherein the configuring the thinsheet of the electrically-conductive material to form the interfaceportion includes forming a peripheral portion configured for aninterference fit with a proximal rim of the shell.
 8. The method ofclaim 7, wherein the peripheral portion has a step.
 9. The method ofclaim 1, further comprising forming a ring electrode on theinsert-molded portion by insert molding.
 10. The method of claim 1,further comprising forming a connector sleeve on the insert-moldedportion by insert molding.
 11. A method of manufacturing a tip electrodeof an electrophysiology catheter, the method comprising: providing ashell having an interior cavity; forming a support member with aninterface portion and an insert-molded portion, including: configuring athin sheet of a first material to form the interface portion; and insertmolding the interface portion with a second material to form theinsert-molded portion, wherein the interface portion is configured toengage with the shell with a distal portion of the insert-molded portionpositioned in the interior cavity of the shell; and mounting the shellonto the support member, wherein the interface portion is engaged withthe shell and a distal peripheral portion of the interface portion hasan interference fit with a proximal opening of the shell.
 12. The methodof claim 11, wherein the configuring the thin sheet of the firstmaterial to form the interface portion includes providing the interfaceportion with an electrical connection member.
 13. The method of claim12, wherein the forming the support member includes exposing a portionof the electrical connection member for connection to a lead wire. 14.The method of claim 12, wherein the electrical connection memberprojects from an opening formed in the interface portion and extendsproximally through the opening.
 15. The method of claim 11, wherein theconfiguring the thin sheet of the first material to form the interfaceportion includes forming the interface portion with an opening throughwhich the insert-molded portion extends.
 16. The method of claim 11,wherein the configuring the thin sheet of the first material to form theinterface portion includes forming an interlock projection.
 17. Themethod of claim 11, wherein the configuring the thin sheet of the firstmaterial to form the interface portion includes forming a peripheralportion configured for an interference fit with a proximal rim of theshell.
 18. The method of claim 17, wherein the peripheral portion has astep.
 19. The method of claim 11, further comprising forming a ringelectrode on the insert-molded portion by insert molding.
 20. The methodof claim 11, further comprising forming a connector sleeve on theinsert-molded portion by insert molding.